JP3490425B2 - Receiving device and receiving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus and a receiving method for performing error control in data transmission by making an automatic retransmission request.

[0002]

2. Description of the Related Art In wireless communication, an error control technique for correcting an error that cannot be recovered by equalization, diversity or the like is widely used in order to realize high quality transmission. Automatic retransmission request (Automatic retransmission request) is one of the error control techniques.
Repeat Request: ARQ (hereinafter, referred to as “ARQ”).

In this ARQ, a transmitting side and a receiving side are connected by a bidirectional transmission path. First, the transmitting side sends a packet including a code word generated by performing error detection coding on information bits to a receiving side. Detects errors. If no error is detected in the received data, the receiving side receives a positive acknowledgment signal (Positive Acknowledgment:
ACK (hereinafter referred to as “ACK”) to the transmitting side, and if an error is detected in the received data, a retransmission request signal (Ne
gative Acknowledgment: NACK, hereafter "NACK"
Is returned to the sender. Upon receiving the NACK, the transmitting side retransmits the same packet. The sending side is ACK
The retransmission of the same packet is repeated until the packet is received.

[0004] For example, a case will be described in which information bits that are blocked are sequentially formed into packets and transmitted. First, the transmitting side transmits the first packet M, and if the receiving side correctly receives the codeword included in the first packet M, it transmits ACK to the transmitting side. The transmitting side has this A
When the CK is received, the next second packet M + 1 is transmitted. Next, on the receiving side, the second packet M
If +1 is erroneously received, a NACK is transmitted to the transmitting side. When the transmitting side receives the NACK from the receiving side, it transmits (retransmits) the second packet M + 1 again. That is, the transmitting side continues to transmit the same packet as the previously transmitted packet M + 1 without transmitting the next new packet M + 2, unless an ACK is received from the receiving side. ARQ achieves high quality transmission in this way.

[0005] Although high quality transmission can be realized in the above-mentioned ARQ, transmission delay may be increased by repeating retransmission. In particular, when the propagation environment is poor, the data error rate increases, so the number of retransmissions increases and the transmission delay increases rapidly. In recent years, hybrid A has been used as a technique for coping with the propagation delay in ARQ.
RQ is being actively studied. Hybrid ARQ is
This is a method in which ARQ is combined with an error correction code, and its object is to improve the error rate of a received signal using error correction, thereby reducing the number of retransmissions and improving the throughput.

[0006] One of the hybrid ARQ schemes is Pack
There is a hybrid ARQ of the et Combining type. Packet C
In the ombining type hybrid ARQ, the transmitting side retransmits the same packet M as the packet M transmitted last time. When the receiving side receives the retransmitted packet M, the codeword (systematic bit and parity bit) included in the previously received packet M and the codeword (systematic bit and (Parity bit), and performs error correction decoding on the combined signal. As described above, in the packet-combining-type hybrid ARQ, the codeword included in the packet M received up to the previous time and the codeword included in the packet M retransmitted this time are combined to improve the reception level, so that retransmission is repeated. Each time, the error rate of the received signal is improved. As a result, the received signal becomes error-free with a smaller number of retransmissions than the ARQ without error correction, so that the throughput can be improved.

[0007]

However, in the above-mentioned hybrid ARQ, AC power is deteriorated due to deterioration of the propagation environment.
K or NACK may be erroneously transmitted to the transmission side. In such a case, a packet different from the packet requested by the reception side may be transmitted from the transmission side.
Specifically, an error is detected in the packet M on the receiving side, and N
When the ACK is transmitted to the transmitting side and the transmitting side receives the ACK, the transmitting side transmits the next packet M + 1. Since the receiving side has issued a retransmission request, the previous packet M is desired to be combined. For this reason, on the receiving side, different packets (packet M and packet M + 1) are combined, and the combination has the opposite effect against the purpose of improving the reception level by the combination. Further, when no error was detected from the decoded data of the packet M on the receiving side and ACK was transmitted to the transmitting side,
When the transmission side receives NACK, the transmission side transmits the previous packet M. Since the receiving side has transmitted the acknowledgment signal ACK, the next packet M + 1 is desired. For this reason, the receiving side decodes the same data as the decoded data even though it has already obtained decoded data in which no error has been detected. As a result,
There is a problem that the throughput is greatly reduced.

As a method for preventing erroneous combining, it is conceivable to determine whether or not a signal is requested on the receiving side based on control data added to the packet. There is a problem in that it cannot be recognized until the decoding process is performed, and the processing amount increases and processing delay occurs.

The present invention has been made in view of such a point, and in data communication using hybrid ARQ, even if a packet different from a packet requested on the receiving side is received, a decrease in throughput can be avoided. An object of the present invention is to provide a receiving device and a receiving method.

[0010]

In order to solve the above-mentioned problems, a receiving apparatus of the present invention deinterleaves a received signal with an interleaving pattern according to a predetermined number of retransmissions with a transmitting side. A deinterleaver that forms a plurality of deinterleaved signals, and a retransmission number determination unit that determines the number of retransmissions by detecting which of the plurality of deinterleaved signals includes a known reference signal. Is adopted.

[0011] According to this configuration, the number of retransmissions of the received packet is determined based on the interleave pattern of the received packet. Therefore, it is not necessary to insert the retransmission number information into the packet. It can be determined whether or not the packet is to be transmitted. As a result, it is possible to avoid an increase in the processing amount in the receiving device and a processing delay.

A receiving apparatus according to the present invention combines and decodes a data series included in a received packet and synthesized data of the same data series received up to the previous time, and decodes the data by the synthesizing decoding means. Error detection means for detecting an error in the received data, when an error is detected, generating a retransmission request signal, and when no error is detected, generating an acknowledgment signal; and the retransmission request signal and the acknowledgment signal. A transmitting means for transmitting to the transmitting side, when a retransmission request signal is transmitted by the transmitting means, when a repetition number determination result indicating the first transmission is obtained by the retransmission number determining means,
And a combining decoding control unit that controls the processing of the combining decoding unit when a number determination result indicating retransmission is obtained by the retransmission number determining unit when the reception confirmation signal is transmitted by the transmitting unit. take.

[0013] According to this configuration, when the receiving apparatus has transmitted a NACK but has erroneously received a packet which is not a retransmission packet, and erroneously received a packet which has not transmitted a ACK even though the receiving apparatus has transmitted an ACK. Is determined as abnormal reception and the combining decoding means is controlled, so that a decrease in throughput caused by abnormal reception can be avoided.

[0014] In the receiving apparatus according to the present invention, the combining / decoding control means, when the retransmission request signal is transmitted by the transmission means and the retransmission number determination means obtains a number determination result indicating the first transmission, Means for controlling the stop of the combination of the data sequence received previously and the data sequence received this time by the means, and when the transmission confirmation means transmits a reception acknowledgment signal, the retransmission number determination means indicates the number of retransmissions indicating the retransmission. Is obtained, control is performed so as not to decode the data sequence received this time.

According to this configuration, when a packet that is not a retransmission packet is erroneously received after the receiving device has transmitted a NACK, combining of different packets can be prevented, and the receiving device transmits the ACK. When the retransmission packet is received erroneously after being transmitted, decoding of the same data again can be prevented. As a result, a decrease in throughput can be avoided.

The receiving apparatus according to the present invention is characterized in that the retransmission number determining means calculates a correlation value between the plurality of deinterleaved signals and a known reference signal predetermined between a transmitting side and And a maximum value detecting means for detecting a maximum correlation value from the plurality of correlation values calculated by the correlation value calculating means.

According to this configuration, of the correlation values obtained by the correlation operation between the plurality of deinterleaved signals and the known reference signal included in the receiving device, the largest correlation value is detected, and the detected interleave pattern is By knowing whether or not it corresponds to the number of retransmissions, the receiving apparatus can know the number of retransmissions of the received packet.

The transmitting apparatus according to the present invention has a plurality of interleave patterns corresponding to the number of retransmissions of a packet, an interleaver interleaving with an interleave pattern corresponding to the corresponding number of retransmissions , and receiving any one of the above interleaved packets. And a transmitting means for transmitting the data to the device.

According to this configuration, the number of retransmissions of the packet can be notified to the receiving side via the interleave pattern.

The receiving method according to the present invention comprises the steps of: forming a plurality of deinterleaved signals by deinterleaving a received signal with a transmitting side in an interleave pattern corresponding to a predetermined number of retransmissions; A retransmission number determining step of determining the number of retransmissions by detecting which of the plurality of deinterleaving signals includes a known reference signal.

According to this method, the number of retransmissions of the received packet is determined based on the interleave pattern of the received packet. Therefore, the information of the number of retransmissions need not be inserted into the packet, and the receiving apparatus can decode the data before decoding the data. It can be determined whether the packet is a packet. As a result, it is possible to avoid an increase in the processing amount in the receiving device and a processing delay.

[0022]

[0023]

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is that a transmitting apparatus performs interleaving of a pilot sequence in a predetermined pattern corresponding to the number of transmissions among a plurality of interleaving patterns, and the receiving apparatus transmits the interleaved pilot sequence to the number of transmissions. Is that the receiving apparatus knows the number of times of transmission of the packet based on a pilot sequence in which the correlation between the deinterleaved pilot sequence and the known pilot pattern is maximized.

Another object of the present invention is to avoid combining the previous combined data with the currently received data or to avoid decoding when the receiving device receives a packet different from the desired packet. As a result, even when the receiving device receives a packet different from the desired packet, it is possible to avoid a decrease in throughput.

An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a data transmission system according to an embodiment of the present invention. As shown in this figure, the transmitting device 100 is connected to the receiving device 200 by a bidirectional transmission path. The transmitting device 100 generates a packet by adding a protocol header, and transmits the generated packet to the receiving device 200. The packet is
This is an example of a data transmission unit, and other data transmission units include a frame and a superframe.

Receiving apparatus 200 receives the packet transmitted from transmitting apparatus 100, demodulates and performs error correction decoding, and performs error detection processing on the decoded result. The receiving device 200
If no error is detected in the decoding result due to the error detection, a reception acknowledgment signal (Positive Acknowledgment: ACK, hereinafter referred to as “ACK”) is sent to transmitting apparatus 100, and if an error is detected in the decoding result, a retransmission request signal ( Negative
Acknowledgment: NACK (hereinafter, referred to as “NACK”) is transmitted to the transmitting apparatus 100.

Upon receiving NACK, transmitting apparatus 100 generates a retransmission packet by multiplexing the same data sequence as the previous retransmission unit and the protocol header, and transmits the generated retransmission packet to receiving apparatus 200. I do. When receiving the retransmission packet, receiving apparatus 200 combines (power combines) the data received up to the last retransmission unit. Then, decoding is performed using the combined sequence. An error is detected from this decoding result, and ACK or NACK is transmitted to transmitting apparatus 100 according to the error detection result. When receiving the NACK, transmitting apparatus 100 generates and transmits a new retransmission packet. The transmitting device 100
Retransmission is repeated until CK is received, and when ACK is received, transmission of the next packet is started.

In this specification, the transmitting device 10
0 transmits a packet, and a processing unit from the reception of the packet to the reception of the ACK or NACK from the reception device 200 to the transmission device 100 is referred to as a “retransmission unit”. Also,
The processing unit from when the transmitting side transmits the same packet for the k-th time until when the ACK or NACK is received is referred to as a “k-th retransmission unit”. A case where an untransmitted packet is transmitted (the first transmission count) is referred to as a first retransmission unit.

Next, the transmitting device 100 and the receiving device 200 will be described in detail.

First, the transmitting device 100 will be described.
FIG. 2 is a block diagram showing an internal configuration of the transmitting device 100. In this figure, coding section 101 performs error detection coding and error correction coding on information bits in order, and outputs a coded signal to storage section 103. The counter 102 counts the number of transmissions of the same packet, and outputs the counted value to the storage unit 103 and the selection circuits 104 and 107. When an ACK is received from the receiving device 200, the count value is reset and the counting is restarted from 1. Storage unit 1
Numeral 03 stores the encoded signal and changes data to be output according to the count value output from the counter 102. That is, when the count value is “1”, untransmitted data is output, and when the count value is “2” or more, the same data as the last time is output. The selection circuit 104 selects one of the interleavers 105-1 to 105-N according to the count value output from the counter 102, that is, the number of times of transmission of the same packet, and connects the storage unit 103 to the selected interleaver. I do.

The interleavers 105-1 to 105-N are:
Different interleave patterns are determined, and each time the number of times of transmission of the same packet increases, an interleaver different from the interleaver used for the previous transmission is used. In the interleaver selected by the selection circuit 104, the data arrangement order is rearranged according to a predetermined rule (interleave pattern) and output to the modulation section 106.

Modulation section 106 has a modulation scheme such as QPSK or 16QAM determined in advance.
A signal interleaved by any of -1 to 105-N is modulated by a predetermined modulation scheme, and the modulated signal is output to multiplexing section 110. The selection circuit 107 selects one of the interleavers 108-1 to 108-N in accordance with the count value output from the counter 102, that is, the number of times of transmission of the same packet, and outputs the input pilot pattern to the selected interleaver. Output.

The interleavers 108-1 to 108-N are:
Different interleave patterns are defined, and each time the number of retransmissions increases, an interleaver different from the interleaver used in the previous retransmission is used. Selection circuit 10
In the interleaver selected by 7, the order of the data is rearranged according to a predetermined rule (interleave pattern) and output to the modulation section 109. In addition, it does not necessarily have the same pattern as the interleavers 105-1 to 105-N.

Modulating section 109 includes interleaver 108-1.
The signal interleaved by any one of .about.108-N is modulated and output to multiplexing section 110. Multiplexing section 110 generates a transmission packet by multiplexing the data signal output from modulation section 106, the pilot signal output from modulation section 109, and the protocol header, and outputs the generated transmission packet to radio transmission section 111. I do. Wireless transmission unit 1
An antenna 1 performs predetermined transmission processing such as frequency conversion and amplification on a transmission packet output from the multiplexing unit 110, and
12 to the receiving device 200.

Next, the receiving apparatus 200 will be described.
FIG. 3 is a block diagram showing the internal configuration of the receiving device 200. Radio reception section 202 performs predetermined reception processing such as frequency conversion on a packet received via antenna 201, and outputs the packet after the reception processing to separation section 203.
Separating section 203 separates the received packet into a pilot sequence and a data sequence. The separated pilot sequence is output to demodulation section 204, and the separated data sequence is output to demodulation section 210.

Demodulation section 204 demodulates the separated pilot sequence and outputs the demodulated pilot sequence to deinterleaver 2.
05-1 to 205-N.

Deinterleavers 205-1 to 205-N
Have an interleave pattern corresponding to the interleavers 108-1 to 108-N on a one-to-one basis, and perform deinterleaving on the demodulated pilot sequence in each pattern. The deinterleaved signal is applied to the correlator 20
6-1 to 206-N.

The correlators 206-1 to 206-N perform a correlation operation between the deinterleaved signal and the known pilot sequence, and output a correlation value as a calculation result to the maximum value detection unit 207. For the known pilot sequence, the same pattern is determined in advance by transmitting apparatus 100 and receiving apparatus 200.

The maximum value detecting section 207 includes a correlator 206-1.
The maximum correlation value is detected from among the correlation values output from ２０６206-N, and it is determined from the maximum correlation value and the interleave pattern corresponding to which retransmission unit this time corresponds to. The determined number of retransmission units is output to storage section 208, determination section 209, and selection section 211. The storage unit 208
The stored previous number of retransmission units is output to determination section 209, and the number of retransmission units output from maximum value detection section 207 is overwritten and stored. The method of determining the number of retransmission units will be described later.

Judging section 209 determines the number of retransmission units based on the last retransmission unit number output from storage section 208 and the current retransmission unit number output from maximum value detection section 207.
It is determined whether the desired packet has been transmitted. The determination result is output to the combining circuit 213 and the error detection unit 217.

[0043] Demodulation section 210 demodulates the separated data series and outputs the demodulated data series to selection section 211.
The selection unit 211 determines the deinterleaver 212 according to the current retransmission unit number output from the maximum value detection unit 207.
One of -1 to 212-N is selected, and a data sequence is output to the selected deinterleaver 212-1 to 212-N.

Deinterleavers 212-1 to 212-N
Have interleave patterns corresponding to the interleavers 105-1 to 105 -N on a one-to-one basis. The deinterleavers 212-1 to 212-N deinterleave the data sequence output to the deinterleaver selected by the selection unit 211, and output the deinterleaved signal to the combining circuit 213. The combining circuit 213 includes an adder 214 and a storage unit 215. The adder 214 combines the data sequence received in the current retransmission unit and the combined data of the data sequence received up to the previous time. The adder 214 overwrites the combined data in the storage unit 215 and outputs the combined data to the decoding unit 216. The storage unit 215 overwrites and stores data that is combined every time retransmission is repeated. Therefore, storage unit 215 stores data obtained by combining all the data sequences received up to the current retransmission unit. When the discard signal is acquired from the determination unit 209 or the ACK is acquired from the error detection unit 217, the held combined data is deleted.

The decoding section 216 performs error correction decoding on the combined symbols output from the combining circuit 213 and outputs the decoded symbols to the error detection section 217. The error detection unit 217 outputs the
Error detection is performed on the signal output from 16 and if there is an error, a NACK is generated, and if there is no error, an ACK is generated. The generated ACK and NACK are transmitted to the transmitting device 100
Sent to. The ACK is also output to the storage unit 208 and the storage unit 215 of the reception device 200.

Next, the operation of the transmitting apparatus 100 and the receiving apparatus 200 when the transmitting apparatus 100 receives an ACK despite the transmitting apparatus 200 transmitting a NACK will be described. The error detector 217 detects an error in the packet M received by the receiver 200 in the (k-1) th retransmission unit, and generates a NACK. The receiving device 200 transmits the generated NACK to the transmitting device 100. The transmitted NACK is affected by fading or the like in the propagation path, and the transmitting device 100 recognizes that the ACK has been received. Upon receiving the ACK, the transmitting device 100 resets the counter 102 and starts transmitting the packet M + 1.

The interleavers 105-1 to 105-N are:
Each has an interleave pattern corresponding to the number of retransmission units.
The interleaver 105-2 corresponds to the second retransmission unit, and the interleaver 105-N corresponds to the Nth retransmission unit. Therefore, in the selection circuit 104, the interleaver 105-1 is selected according to the count value (the number of retransmission units) "1" indicated by the counter 102, and the interleaver 105-1 is connected to the storage unit 103. Storage unit 103
Are output from the interleaver 105-1.
And the multiplexing unit 11 via the modulation unit 106
Output to 0.

Similarly to selection circuit 104, selection circuit 107 selects interleaver 108-1 according to the number of retransmission units "1" indicated by counter 102, and outputs a pilot sequence to interleaver 108-1. The pilot sequence is interleaved in interleaver 108-1;
Output to multiplexing section 110 via modulation section 109.

Multiplexing section 110 multiplexes the modulated data sequence, the modulated pilot sequence, and the protocol header, and transmits the multiplexed data sequence to receiving apparatus 200 via radio transmitting section 111 and antenna 112, respectively.

Packet M transmitted from transmitting apparatus 100
+1 is received by the receiving device 200. Separating section 203 separates the signal into a pilot sequence and a data sequence. The separated pilot sequence is demodulated by demodulation section 204,
Deinterleaving is performed by all of the deinterleavers 205-1 to 205-N. Deinterleaver 205-1 to 205-
The pilot sequences deinterleaved in all N are correlated with known pilot patterns by correlators 206-1 to 206-N, and the calculated correlation values are output to maximum value detecting section 207. The maximum value detection unit 207 detects the maximum correlation value among the correlation values output from the correlators 206-1 to 206-N. In this case, since the interleaving pattern of interleaving 108-1 is used on the transmitting side, the pilot sequence output from deinterleaving 205-1 has the largest correlation value. That is, maximum value detecting section 207 determines that packet M + 1 transmitted from transmitting apparatus 100 is a packet of the first retransmission unit. The number of retransmission units “1” determined by the maximum value detection unit 207 is output to the storage unit 208, the determination unit 209, and the selection unit 211.

In storage section 208, determination section 209 is notified of the stored retransmission unit number “k−1”. Then, the retransmission unit number “1” output from the maximum value detection unit 207 is newly overwritten and stored. Selector 211
In, the deinterleaver 212-1 corresponding to the retransmission unit number “1” output from the maximum value detection unit 207 is selected, and the data sequence of the packet M + 1 is
Output to 2-1. The data sequence input to the deinterleaver 212-1 is deinterleaved, and
13 is output.

In determination section 209, the packet transmitted this time is the packet desired by the receiving apparatus based on the number of retransmission units notified from storage section 208 and the number of retransmission units determined in maximum value detection section 207. Is determined. The number of retransmission units notified from the storage unit 208 is “k−1”, and the packet desired by the receiving device 200 is a packet of the k-th retransmission unit. However, the retransmission unit number output from the maximum value detection unit 207 is “1” (the first transmission which is the first transmission).
It indicates that the packet is not a packet desired by the receiving apparatus 200. The determination unit 209 sends the storage unit 21 to the combining circuit 213 based on the determination result.
The instruction to discard the combined data up to the (k-1) -th retransmission unit stored in No. 5 is issued.

Thus, even if the receiving apparatus 200 receives a packet M + 1 different from the desired packet M,
The combined data of the packet M up to the (k-1) th retransmission unit and the first data
Combination with the data sequence of the packet M + 1 in the retransmission unit can be prevented. That is, if the packet M and the erroneously transmitted packet M + 1 are combined, there is a possibility that both may not be decoded. However, by performing the above-described processing, the erroneously transmitted first retransmission unit packet M + 1 is decoded. And a decrease in throughput can be avoided.
Note that the combined data of the packet M up to the (k-1) -th retransmission unit stored in the receiving device 200 is discarded,
Retransmission processing is performed by the upper layer. Further, a configuration in which the receiving apparatus 200 notifies the transmitting apparatus 100 of returning to the retransmission unit of the packet M may be considered. With this configuration, the number of packets to be discarded can be reduced, and a decrease in throughput can be avoided.

Next, the operation of transmitting apparatus 100 and receiving apparatus 200 in the case where transmitting apparatus 100 receives NACK despite receiving apparatus 200 transmitting ACK will be described. Packet M received by receiving device 200
Are not detected by the error detection unit 217, and ACK is generated. The receiving device 200 transmits the generated ACK to the transmitting device 100. The transmitted ACK is affected by fading or the like in the propagation path, and the transmitting device 100
It recognizes that ACK has been received. The transmitting device 100 is NAC
Upon receiving K, the counter 102 is incremented and the packet M is retransmitted. The retransmission unit at this time is referred to as a k-th retransmission unit (k ≠ 1).

Transmitting apparatus 100 interleaves a pilot sequence to be multiplexed on packet M using interleaver 108-k corresponding to the k-th retransmission unit. Similarly, a data sequence to be multiplexed on packet M is interleaved using interleaver 105-k corresponding to the k-th retransmission unit. The packet M of the k-th retransmission unit interleaved in this way
Is transmitted to the receiving device 200.

Packet M transmitted from transmitting apparatus 100
Is received by the receiving device 200. The pilot sequence is deinterleaved by all of the deinterleavers 205-1 to 205-N. Deinterleaver 205-1 to 205-N
Are subjected to correlation calculation with known pilot patterns in correlators 206-1 to 206-N, and the calculated correlation value is output to maximum value detection section 207. The maximum value detection unit 207 detects the maximum correlation value among the correlation values output from the correlators 206-1 to 206-N. In this case, since the interleave pattern of interleave 108-k is used on the transmission side, the pilot sequence output from deinterleave 205-k takes the maximum correlation value. That is, maximum value detecting section 207 determines that packet M transmitted from transmitting apparatus 100 is a packet in the k-th retransmission unit. The number of retransmission units “k” determined by the maximum value detection unit 207 is stored in the storage unit 208, the determination unit 209, and the selection unit 2
11 is output.

Since ACK has already been acquired from error detecting section 217 in storage section 208, “0” is stored, and determination section 209 is notified of the number of retransmission units “0”.
Further, the retransmission unit number “k” output from the maximum value detection unit 207 is newly overwritten and stored. Selector 211
In, the deinterleaver 212-k corresponding to the retransmission unit number “k” output from the maximum value detection unit 207 is selected, and the data sequence of the packet M is
k. The data sequence input to the deinterleaver 212-k is deinterleaved, and
Is output to

In determination section 209, the packet transmitted this time is the packet desired by the receiving apparatus based on the number of retransmission units notified from storage section 208 and the number of retransmission units determined in maximum value detection section 207. Is determined. The number of retransmission units notified from the storage unit 208 is “0”,
The packet desired by the receiving device 200 is a packet of the first retransmission unit. However, the retransmission unit number output from the maximum value detection unit 207 is “k” (indicating retransmission), and it is determined that the packet is not a packet desired by the receiving device 200.
The determination unit 209 determines the combination of the combining circuit 2
13 for the data sequence of the packet M
Is output, and an instruction is issued to the error detection unit 217 to generate ACK again.

In the combining circuit 213, since the storage unit 215 has already acquired the ACK, there is no stored combined data, and the data series of the packet M is not combined by the adder 214. In addition, the combining circuit 213 includes a determination unit 209.
Since the instruction to stop outputting the data sequence of the packet M to the decoding unit 216 has been received, the adder 214
Are output only to the storage unit 215.

The error detecting section 217 generates an ACK again according to the instruction of the determining section 209, transmits the generated ACK to the transmitting apparatus 100, and outputs the generated ACK to the storage section 208 and the storage section 215. Thereby, the transmitting device 100
Starts the process of receiving the ACK and transmitting the next packet M + 1, which is an untransmitted packet. On the other hand, the receiving device 20
At 0, the storage unit 208 obtains an ACK, thereby resetting the stored number of retransmission units “k”. The storage unit 215 also obtains an ACK, so that the data sequence of the stored packet M is changed. Will be erased.

As described above, even if the packet desired by the receiving device 200 is the packet M + 1 of the first retransmission unit, the data sequence of the packet M is not decoded even if the retransmission packet of the packet M is received. The data of the packet M that can be discarded and has already been decoded without any error detected does not need to be decoded again. As a result, a decrease in throughput can be avoided.

Next, a method for determining the number of retransmission units using a pilot sequence will be described in detail. FIG. 4 is a schematic diagram showing an interleaving process for each retransmission unit number according to the embodiment of the present invention. In FIG. 4, the pilot sequence is 8
The symbol sequence (P) is P = (S
_{1, S 2, S 3,} S 4, S 5, S 6, S 7, S 8) = (1, -
1,1, -1,1, -1, -1, -1, -1). Also,
The interleave pattern applied to the first retransmission unit is IL1
= (1, 5, 2, 8, 4, 7, 6, 3). This I
When interleaves L1 is performed, S ₁ is the forward in the input symbol sequence _{S 1 ~S 8, S 5,} S 2, S 8, S 4,
S _7, S _6, and sorted in the order of S ₃ is output. Similarly, the interleave pattern applied to the second retransmission unit is represented by I
L2 = (8, 1, 4, 7, 6, 3, 2, 5) and the third
The interleave pattern applied to the retransmission unit is IL3 =
(2, 7, 8, 6, 3, 5, 5, 4, 1). Here, the second retransmission unit will be described.

In transmitting apparatus 100, counter 102 indicates “2”, and selection circuit 107 selects IL2 corresponding to the second retransmission unit. The pilot sequence is interleaved with IL2 of interleaver 108-2. I
Interleaving and deinterleaving using L2 will be described with reference to FIG. As shown in this figure, the arrangement order of the pilot sequences before interleaving is rearranged in accordance with the pattern indicated by IL2, and the arrangement order indicated by IL2 is the arrangement order of the pilot sequences after interleaving. Specifically, since the first element is 8 IL2, S ₈ is an 8-th interleaving previous pilot sequence is a first interleaved, because 1 is the second element of IL2, the pilot sequence S ₁ is the first becomes the second interleaved. Thus, the rearrangement is performed for all pilot sequences. As a result, the pilot sequence after interleaving (referred to as P ′) is P ′ = (S ₈ , S ₁ , S ₄ ,
S ₇ , S ₆ , S ₃ , S ₂ , S ₅ ) and are transmitted to the receiving device 200.

Deinterleaving in receiving apparatus 200 performs a process of returning interleaved sequence P ′ to original sequence P before interleaving. That is, the arrangement order of the interleaved pilot sequences is rearranged in the numerical order indicated by IL2. Specifically, it rearranges the S ₈ is the first element of the interleaved symbol sequence P 'in order (8) indicated by the first element of IL2. Similarly, the second element S ₁ of the interleaved symbol sequence P ′ is
Rearrange in the order (1) indicated by the second element of L2. In this way, by rearranging all the pilot sequences P ′ after interleaving, it is possible to return to the pilot sequence P before interleaving.

In the present embodiment, interleaved pilot sequence P 'is deinterleaved with all interleaving patterns. This is shown in FIG. FIG. 6 shows the interleave patterns IL1 to IL3 used in FIG.
Are sorted by IL1 to IL3. P '
= (S ₈ , S ₁ , S ₄ , S ₇ , S ₆ , S ₃ , S ₂ , S ₅ )
When deinterleaving is performed in L1, P1 ′ = (S ₈ , S ₄ ,
_{S 5, S 6, S 1} , S 3, S 2, the S _7). Similarly, P '
Is deinterleaved by IL2, P2 ′ = (S ₁ ,
S ₂ , S ₃ , S ₄ , S ₅ , S ₆ , S ₇ , S ₈ ), and when P ′ is deinterleaved with IL3, P 3 ′ = (S ₅ ,
_{S 8, S 6, S 2} , S 3, S 7, S 1, S 4) and composed. As a result, P ≠ P1 ′, P = P2 ′, and P ≠ P3 ′. Only when deinterleaving is performed by the receiving device using the same interleaving pattern used when interleaving by the transmitting device, the transmission side The same sequence can be obtained. In practice, the correlator correlates with a known pilot pattern and detects a pilot sequence having the largest correlation value, thereby recognizing the same sequence as the transmitting side.

Here, a determination method using a correlator will be described. In the propagation path, the pilot sequence is distorted due to the influence of noise, and a high-accuracy correlation value can be obtained by performing a correlation operation using the following equation (1).

(Equation 1)

Here, C_mIs the data corresponding to the m-th retransmission unit.
The output from the correlator connected to the interleaver, where N is
Lot sequence length, p '_m,_jCorresponds to the m-th retransmission unit.
I of the pilot sequence deinterleaved by Lever
Th element, p_iIs the ith element of the known pilot sequence
It is. FIG. 6 shows the result of calculating the correlation value according to this equation.
It was shown to. The known pilot pattern is (S₁, S_Two, S
_Three, S_Four, S_Five, S₆, S ₇, S₈). Also, S₁~ S₈
Has the numerical values used in FIG. By IL1 and IL3
Deinterleaved pilot sequences and known pilots
The correlation value with the pattern shows 0.5. By IL2
Deinterleaved pilot sequences and known pilots
The correlation value with the pattern is 1, which is the largest correlation value.
You.

In this embodiment, for simplicity of description, a regular pattern P = (1, -1,1, -1,1, -1,1, -1,) is used as a pilot pattern. Although used, in order to reduce the correlation value when the receiving side deinterleaves with a different interleaving pattern from the transmitting side, it is desirable to use a sequence in which the cross-correlation value of another sequence becomes small, such as an M sequence or a GOLD sequence. . In the above description, the sequence length is set to 8, but it is desirable to use a sequence length that reduces the correlation value between different interleave patterns. The interleaving and deinterleaving methods described above are merely examples, and there are other methods of rearranging according to a predetermined rule.

In the present embodiment, transmission apparatus 100
Bit interleaving, which performs interleaving before modulation in modulation sections 106 and 109 and performs deinterleaving after demodulation in demodulation sections 204 and 210 of receiving apparatus 200, has been described.
It is also easy to apply symbol interleaving in which interleaving is performed after modulation by modulation sections 106 and 109 of 0 and deinterleaving is performed before demodulation by demodulation sections 204 and 210 of receiving apparatus 200.
By performing interleaving and deinterleaving with modulation symbols, the amount of data to be interleaved is reduced, so that the processing amount can be reduced.

Further, in the present embodiment, the case where bit interleaving is used for both pilot and data has been described.
A configuration using symbol interleaving for pilot and bit interleaving for data is also possible.

Further, after being modulated by modulation section 106 and modulation section 109 of transmitting apparatus 100, the signal is spread and received by receiving apparatus 2.
CDMA (Code Division Multiple A) that performs despreading before demodulation by the demodulation units 204 and 210
ccess) In a system, it is also possible to adopt a configuration in which interleaving and deinterleaving are performed with chips after spreading.

With such a configuration, by interleaving and transmitting the pilot pattern with a different interleave pattern for each retransmission unit, it becomes possible for the receiving side to know the number of retransmission units this time, and only the same packet can be combined. Become. As a result, the throughput can be improved. Also, there is no need to separately transmit the number of retransmission units subjected to error correction, and at the same time, there is no need for decoding, so that the processing amount of the receiving apparatus can be significantly reduced,
Since no processing delay occurs, the throughput can be improved.

The data transmission system of the present embodiment can be applied to a digital wireless cellular system.
In this case, the receiving device 200 is mounted on a communication terminal that freely moves in a cell, and the transmitting device 100 is mounted on a base station.
By performing the ARQ process between the transmitting apparatus 100 and the receiving apparatus 200, it is possible to improve the transmission quality and the throughput in wireless communication. The receiving device 200 is mounted on the base station, and the transmitting device 10 is mounted on the communication terminal.
0 may be mounted.

In the present embodiment, the first transmission and the retransmission are collectively treated as “the number of retransmission units”, but are described as “the number of retransmissions” in the claims. Both are synonymous.

[0075]

As described above, according to the present invention,
A plurality of interleave patterns corresponding to the number of transmissions of the same packet are known between the transmission and reception apparatuses, and the reception apparatus knows the number of transmissions of the received packet based on the interleave pattern, so that the reception apparatus determines whether the desired packet is transmitted. The determination can be made without performing the decoding process, and the processing amount and the processing delay can be reduced. If the received packet is not the packet desired by the receiving device, the receiving device receives a packet different from the packet desired by the receiving device by avoiding combining with the previous combined data or avoiding decoding. Even in this case, a decrease in throughput can be avoided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a data transmission system according to an embodiment of the present invention;

FIG. 2 is a block diagram showing an internal configuration of a transmitting apparatus according to the embodiment of the present invention.

FIG. 3 is a block diagram showing an internal configuration of a receiving apparatus according to the embodiment of the present invention.

FIG. 4 is a schematic diagram showing an interleaving process for each retransmission unit number according to the embodiment of the present invention.

FIG. 5 is a schematic diagram showing a deinterleaving process for each retransmission unit number according to the embodiment of the present invention.

FIG. 6 is a diagram showing interleaving and deinterleaving processing according to the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 101 Encoding section 102 Counters 103, 208, 215 Storage sections 104, 107 Selection circuits 105-1 to 105-N, 108-1 to 108-N Interleavers 106, 109 Modulation section 110 Multiplexing section 111 Radio transmission section 202 Radio reception section 203 Separation sections 204, 210 Demodulation sections 205-1 to 205-N, 212-1 to 212-N Deinterleavers 206-1 to 206-N Correlator 207 Maximum value detection section 209 Judgment section 211 Selection section 213 Synthesis circuit 214 Addition Unit 216 decoding unit 217 error detection unit

   ────────────────────────────────────────────────── ─── Continuation of front page       (56) References JP 2001-60934 (JP, A)                 International Publication 00/002341 (WO, A1)

Claims (6)

(57) [Claims] 1. A deinterleaver for forming a plurality of deinterleaved signals by deinterleaving a received signal with an interleave pattern corresponding to a predetermined number of retransmissions with a transmitting side; A receiving apparatus comprising: a retransmission number determination unit that determines a retransmission number by detecting which deinterleaved signal contains a known reference signal among signals. 2. Synthesizing and decoding means for synthesizing and decoding a data series included in a received packet and synthesized data of the same data series received up to the previous time, and detecting an error in the data decoded by the synthesizing decoding means. And when an error is detected, generate a retransmission request signal,
When no error is detected, an error detection unit that generates a reception confirmation signal, a transmission unit that transmits the retransmission request signal and the reception confirmation signal to a transmission side, and that the transmission unit transmits a retransmission request signal. When the number determination result indicating the first transmission is obtained by the retransmission number determination means, and when the number determination result indicating the retransmission is obtained by the retransmission number determination means when the reception confirmation signal is transmitted by the transmission means, The receiving apparatus according to claim 1, further comprising: combining decoding control means for controlling processing of the combining decoding means. 3. The combining / decoding control means, when a retransmission request signal is transmitted by the transmitting means and a number determination result indicating the first transmission is obtained by the retransmission number determination means, until the previous time in the combining means. When the combined data of the received data sequence and the data sequence received this time are controlled to stop, and when a transmission confirmation signal is transmitted by the transmitting means, a repetition number determination result indicating the retransmission is obtained by the retransmission number determination means. 3. The receiving apparatus according to claim 2, wherein control is performed so that decoding of the data sequence received this time is not performed. 4. The correlation value calculation means for calculating a correlation value between the plurality of deinterleaved signals and a known reference signal predetermined between a plurality of deinterleaved signals and a transmission side; The receiving apparatus according to claim 1, further comprising: a maximum value detecting unit configured to detect a maximum correlation value from the plurality of correlation values calculated by the unit. 5. An interleaver having a plurality of interleave patterns corresponding to the number of retransmissions of a packet and interleaving with an interleave pattern corresponding to the number of retransmissions, and interleaved packets according to claim 1 to 4 .
A transmitting device, comprising: transmitting means for transmitting to the receiving device according to any one of the above. 6. A step of forming a plurality of deinterleaved signals by deinterleaving a received signal with an interleaving pattern according to a predetermined number of retransmissions with a transmitting side; A retransmission number determining step of determining the number of retransmissions by detecting which deinterleaved signal contains a known reference signal.